A patient-friendly sprayable rapid gelation powder (SRGP) with prolonged mucoadhesion for oral ulcer therapy

Recurrent aphthous ulceration (RAU) is a common oral condition that significantly affects patients' quality of life worldwide. Mucosal dressings for wound healing and drug delivery are essential in RAU management. The dynamic and moist environment of the oral cavity poses major obstacles to localized drug delivery, particularly in terms of patient self-administration and dressing retention. In this study, we present a universal oral mucosal drug delivery system based on sprayable rapid gelation powder (SRGP) composed of multigroup-modified alginate, which can be evenly sprayed onto ulcers in different locations within the oral cavity using a low-cost, commercially available plastic spray bottle. Upon contact with the wound, SRGP absorbs saliva and forms an adhesive hydrogel barrier in 2 s, which can continuously release the drug for over 12 h, even in the presence of saliva and oral activities. When loaded with drugs such as lidocaine hydrochloride and dexamethasone sodium phosphate, experiments in rat and dog models demonstrated that drug loaded SRGP significantly reduced inflammation at the ulcer site and reduced wound healing time by 2–3 days compared to commercial dressings. Furthermore, the powder formulation of SRGP can be stored a long time for 24 months, highlighting its potential as a clinical hydrogel dressing for oral ulcers.